"Climate is what we expect," Mark Twain observed, "weather is what we get." At a time when both terms have become politically charged, it's more important than ever to observe the distinction.

The Met Office, whose story is told in the Observer magazine today , started out saving the lives of those in peril on the sea. Today it finds itself in the stormy waters of the news agenda, making judgments on when to dispatch gritting lorries in winter and whether barbecues will be fired up in summer, while predicting average temperatures in 50 years' time. It is ignored when right, pilloried when wrong.

Much as we would like to believe forecasting is an exact science, some parts of it are always going to be more precise than others. Nobody is better than the Met Office at telling you what will happen in your back garden in the next three days, or better qualified to predict the kind of climate we can expect in a decade, or a century. They might sometimes make mistakes, but we should still look to them for guidance and remember that the alternative is looking at the sky in ignorance.